Even in your example there's a world of difference. "Your credentials have been denied" implies a problem with credentials, while 403 clearly states that the cr

Even in your example there's a world of difference. "Your credentials have been denied" implies a problem with credentials, while 403 clearly states that the credentials are valid, they are just denied access to this resource. I know it is a made up example, but it does show the problem with "dumbing down" the error messages. Details matter.